On Tuesday, Tony Blair, British Prime Minister, warned that efforts to secure the 15 Royal Navy personnel captured by Iran could "move into a different phase" as Tehran rejected any attempt to "politicize" the case. Blair said, "I hope we manage to get them (the Iranians) to realize they have to release them. If not, then this will have to move into a different phase."

He went on to say that it is unacceptable for British servicemen and women to be seized when they are in Iraqi waters under a UN mandate, patrolling perfectly rightly and in accordance with that mandate, and then effectively captured and taken to Iran.

Meanwhile, British Foreign Secretary Margaret Beckett, who is visiting Turkey, stressed her government was continuing to seek a diplomatic solution to the crisis over the sailors and Royal Marines, captured in the northern Gulf last Friday.

According to BBC, 14 men and one woman were being held at an Iranian Revolutionary Guards Corps base in Tehran. On Tuesday, Iran said they reject any efforts by London to "politicize" the case of the Royal Navy personnel, captured during a routine patrol.

Britain has categorically rejected Iranian allegations that the group had violated Iranian waters, and claim that they were on patrol in Iraqi waters when seized.

Blair's spokesman explained that the "different phase" referred to "a different way" of handling talks, which may involve making public the reasons why the UK was certain the personnel were in Iraqi waters. He added that there was a difference between doing things privately and going public "because it's a simple fact of life that when you get into public exchanges it sometimes becomes more difficult for people to move. However, we want people and the international community in particular, to be in no doubt that we believe we are in the right in this case."

Beckett said the British government has still not been told the exact whereabouts of the navy personnel but that she welcomed an Iranian statement that they were being held in reasonable circumstances and dismissed the possibility of the captives facing charges of espionage in Iran, as has been suggested, stressing that the navy crew were in Iraqi waters at the time of their detention.